The Effect of a Graded Band Gap Window on the Performance of a Single Junction AlxGa1-xAs/GaAs Solar Cell

We have modeled the effect of a graded band gap window on the performance of a single junction AlxGa1-xAs/GaAs solar cell. First, we study the electrical characteristics of a single junction AlxGa1-xAs/GaAs solar cell, by employing an optimized structure for this solar cell, we show that grading the band gap of the window can increase the conversion efficiency of the solar cell by about 1.5%, and can also improve the quantum efficiency of the solar cell especially at shorter wavelengths.




References:
[1] B. Danilchenko, et al., "1MeV electron irradiation influence on GaAs
solar cell performance", Solar Energy Materials & Solar Cells 92 (2008)
1336-1340.
[2] Martin A. Green, Keith Emery, Yoshihiro Hishikawa, Wilhelm Warta,
"Solar cell efficiency tables (Version 33)", Prog. Photovolt: Res. Appl.
2009; 17:85-94.
[3] A. F. Meftah, N. Sengouga, A. M. Meftah, S. Khelifi, "Numerical
simulation of the effect of the Al molar fraction and thickness of an
AlxGa1-xAs window on the sensitivity of a p+-n-n+ GaAs solar cell to 1
MeV electron irradiation", Renewable Energy 34 (2009) 2426-2431.
[4] B. Li, et al., "High efficiency AlxGa1-xAs/GaAs solar cells: Fabrication,
irradiation and annealing effect", Solar Energy Materials & Solar Cells
44 (1996) 63-67.
[5] http://rredc.nrel.gov/solar/spectra/am0/
[6] V. M. Andreev, V. V. Komin, I. V. Kochnev, V. M. Lantratov, M. Z.
Shvarts, "High-efficiency AlGaAs-GaAs solar cells with internal bragg
reflector", CH3365-4/94/0000-1894 $4.00 ┬® 1994 IEEE.
[7] X. B. Xiang, W. H. Du, X. L. Chang, H. R. Yuan, "The study on high
efficient AlxGa1-xAs/GaAs solar cell", Solar Energy Materials & Solar
Cells 68 (2001) 97-103.
[8] M. Z. Shvarts, O. I. Chosta, I. V. Kochnev, V. M. Lantratov, V. M.
Andreev, "Radiation resistant AlGaAs/GaAs concentrator solar cells
with internal bragg reflector", Solar Energy Materials & Solar Cells 68
(2001) 105-122.
[9] Silvaco International, Atlas User-s Manual, 2007.
[10] http://pvcdrom.pveducation.org/index.html
[11] Arturo Morales-Acevedo, "Effective absorption coefficient for graded
band gap semiconductors and the expected photocurrent density in solar
cells", Solar Energy Materials & Solar Cells 93 (2009) 41- 44.